Blast furnace productivity and the influencing parameters Jun23

Blast furnace productivity and the influencing parameters...

Blast furnace productivity and the influencing parameters Blast furnace (BF) is a process of iron making. During mid eighties BF technology got established and left behind other technologies of iron making. Since then continuous developments are taking place in this technology to make it more productive and economical. Even today it is offering very stiff opposition in the development of alternative iron smelting processes. The blast furnace is a counter current reactor in which the reducing gas is produced by the gasification of the carbon of the coke with the oxygen of the hot blast injected via tuyeres in the lower part of the furnace. The reducing gas flows upwards reducing the iron bearing materials charged at the top of the furnace. Blast furnace process consists of a multivariate system which is subjected to a large number of inter-influencing variables affecting the performance of the blast furnace. It is necessary to isolate the inter-influence of the variables to understand the role played each variable on the performance of the blast furnace. The performance of a blast furnace is determined by many parameters out of which productivity is the major one. The blast furnace productivity is the quotient between possible gas throughput per unit of time and required specific gas generation for one ton of hot metal (HM). Hence an increase in the productivity on the one hand requires an increase in the gas throughput, which implies improvement in the furnace permeability and on the other hand a reduction in the specific gas requirement, which means a reduction in the specific consumption of reducing agent. Blast furnace productivity is usually expressed in tons of hot metal produced/day/Cum of working volume. In some countries, in place of working volume, useful volume is considered. There are many factors which...

Metallurgical coke

Metallurgical coke Metallurgical coke or Met coke in short is a hard carbon material produced in the process of the “destructive distillation” of various blends of bituminous coal. It is produced by carbonization of coal at high temperatures (1100°C) in an oxygen deficient atmosphere in a coke oven. A good quality coke is generally made from carbonization of good quality coking coals. Coking coals are defined as those coals that on carbonization pass through softening, swelling, and re-solidification to coke. One important consideration in selecting a coal blend is that it should not exert a high coke oven wall pressure and should contract sufficiently to allow the coke to be pushed from the oven. The properties of coke and coke oven pushing performance are influenced by following coal quality and battery operating variables: rank of coal, petrographic, chemical and rheologic characteristics of coal, particle size, moisture content, bulk density, weathering of coal, coking temperature and coking rate, soaking time, quenching practice, and coke handling. Coke quality variability is low if all these factors are controlled. The coal-to-coke transformation takes place as follows: The heat is transferred from the heated brick walls into the coal charge. From about 375°C to 475°C, the coal decomposes to form plastic layers near each wall. At about 475°C to 600°C, there is a marked evolution of tar, and aromatic hydrocarbon compounds, followed by re-solidification of the plastic mass into semi-coke. At 600°C to 1100°C, the coke stabilization phase begins. This is characterized by contraction of coke mass, structural development of coke and final hydrogen evolution. During the plastic stage, the plastic layers move from each wall towards the center of the oven trapping the liberated gas and creating in gas pressure build up which is transferred to the heating...